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Beginner

BGP continuosly flapping

Hi,

 

         I'm getting below logs in my router frequently and BGP flaps. could someone tell me what are the possible causes of this issue.

 

Oct 2 02:33:50: %BGP-3-NOTIFICATION: received from neighbor 192.168.181.217 4/0 (hold time expired) 0 bytes

Oct 2 02:33:50: %BGP-5-ADJCHANGE: neighbor 192.168.181.217 Down Peer closed the session

Oct 2 02:33:50: %BGP_SESSION-5-ADJCHANGE: neighbor 192.168.181.217 IPv4 Unicast topology base removed from session  Peer closed the session

Oct 2 02:33:57: %BGP-5-ADJCHANGE: neighbor 192.168.181.217 Up

Oct 2 03:35:52: %BGP-3-NOTIFICATION: received from neighbor 192.168.181.217 4/0 (hold time expired) 0 bytes

Oct 2 03:35:52: %BGP-5-ADJCHANGE: neighbor 192.168.181.217 Down Peer closed the session

Oct 2 03:35:52: %BGP_SESSION-5-ADJCHANGE: neighbor 192.168.181.217 IPv4 Unicast topology base removed from session  Peer closed the session

Oct 2 03:36:03: %BGP-5-ADJCHANGE: neighbor 192.168.181.217 Up

6 REPLIES 6
VIP Advisor

HelloCheck your connectivity

Hello

Check your connectivity to this address as to why it's losing its peering

Res

Paul

 

 



kind regards
Paul

Please rate and mark posts accordingly if you have found any of the information provided useful.
It will hopefully assist others with similar issues in the future
Contributor

Hi,As Paul suggested check

Hi,

As Paul suggested check your connectivity, run an extended ping between BGP peers, might be as simple as layer 1 issue. Else check that you don't have recursive lookup for peer address where by you are peering with an address you you receive via BGP peering.

/Samir 

Highlighted
Beginner

Hi,       There is no L1

Hi,

       There is no L1 issue. it is confirmed.

Advocate

Hi,Hi, is the neighbor within

Hi,

Hi,

 

is the neighbor within the same subnet as your router? Or multiple hops away?

Are you using correct AS number?

Did you try to debug the BGP session?

 

Best regards,

Milan

 

Contributor

Are you dropping packets when

Are you dropping packets when you use an extended ping between sources and destination BGP peers.

How are routes known for next hop peer address.

Of course above assumes you are peering between loopbacks, else disregard my questions.

 

/Samir

 

Beginner

Its look like you are getting

Its look like you are getting (BGP hold time expired) messages, it means that you are missing hellos between neighbors, it could be possible when you are receiving so much traffic and it causes to BGP to miss some hellos.

Please check you interface status.

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